package seqlist.leetcode;

/**
 * 删除排序链表的重复元素，重复元素保留1次
 */
public class Num83 {
    public ListNode deleteDuplicates(ListNode head) {
        ListNode dummyHead = new ListNode(101);
        dummyHead.next = head;
        // prev指向第一个不重复元素
        ListNode prev = dummyHead;
        ListNode cur = prev.next;
        while (cur != null) {
            if (prev.val == cur.val) {
                // 此时cur需要删除
                prev.next = cur.next;
            }else {
                // prev和cur不是重复元素，都向后移动一个单位
                prev = prev.next;
            }
            cur = cur.next;
        }
        return dummyHead.next;
    }
}
